But, just being one marble's worth of space in a phone, it has weaknesses. For example: low light.
- It's harder to hold still due to ergonomics and size.
- The sensor is very small, so gets grainy in high-ISO/low light settings.
- There is no stabilization (no space for it I guess).
Another factor is that you can't set anything yourself on the iPhone, no control over aperture, shutter speed, or ISO. Most of the time, not a problem though.
Also, even with a good pocket camera made in the last couple of years, I'd probably get decent image quality at ISO 800, which would have made for F:2.4 and 1/80th second, much easier to hand-hold.